in single player, hoppers sent items downwards if there is a hopper pulling them out, not to the object they are directed to.
On servers, in the same scenario, hoppers will give priority to the object that it is directed to, not the hopper that is pulling below it.
Duplicate of MC-6162, please use the search function to see if your bug has already been submitted. Currently over 53% of tickets are being closed as duplicate.